1. Field of the Invention
The present invention relates to a radiotherapy apparatus controller and an irradiation method, and more particularly relates to a radiotherapy apparatus and an irradiation method that are used when a tumor area inside a subject is irradiated with a therapeutic radiation.
2. Description of Related Art
Radiotherapy is known in which a patient is treated by irradiating an affected area (tumor) with a therapeutic radiation. As for the radiotherapy, a therapeutic effect is desired to be high. The therapeutic radiation is desired such that a dose of the radiation radiated into normal cells is smaller than a dose of the radiation radiated into cells of the affected area. For this reason, the therapeutic radiation is required to be accurately radiated to the affected area. The radiotherapy apparatus for performing the radiotherapy includes an imager system for imaging a transmission image of the affected area, a therapeutic radiation radiating device for radiating the therapeutic radiation, and a driver for driving the therapeutic radiation radiating device. The radiotherapy apparatus calculates the position of the affected area based on the transmission image and drives the therapeutic radiation radiating device by using the driver such that the therapeutic radiation is radiated to the calculated position.
A supporting structure that supports the therapeutic radiation radiating device and the imager system sags under its own weight and the weight of the therapeutic radiation radiating device. For this reason, when the supporting structure is moved, there is a case that a different visual field deviated from a desirable visual field is projected on the transmission image of the patient. At this time, in a positioning operation of an irradiation target and a positioning accuracy testing, erroneous information is given to a user. It is desired to accurately execute the positioning operation of the irradiation target and the positioning accuracy testing.
Japanese Laid-Open Patent Application JP-A-Heisei 10-234715 (corresponding to U.S. Pat. No. 6,341,172 (B1)) discloses an improved medical imaging system. The medical imaging system is characterized in that this includes an image detector which is configured to receive an image projected by a radiation beam and convert the image into a visual image, the visual image defining a remarkable signal with an upper limit/boundary and a lower limit/boundary, a video detector actively coupled to the image detector, the video detector receiving the visual image and generating a histogram from the visual image, and a video processing circuit, the video processing circuit being configured to automatically identify the upper limit/boundary of the remarkable signal from the histogram.
Japanese Laid-Open Patent Application JP-P 2001-503176A (corresponding to U.S. Pat. No. 5,784,431(A)) discloses an apparatus that can be used to control the radiotherapy apparatus. The apparatus is the apparatus for automatically comparing a portal image and a simulation image. This is provided with a means for digitizing the portal image and the simulation image and respectively generating a digital portal image signal (DPIS) and a digital simulation image signal (DSIS); a processing means for processing the DPIS and the DSIS and generating already-compared DPIS and DSIS; and a means for generating outputs from the already-compared DPIS and DSIS.
Japanese Laid-Open Patent Application JP-P 2006-149438A discloses an irradiation position matching system for supporting a position matching of an irradiation part, which is good in convenience and excellent in reproduction and based on an irradiation plan. The irradiation position matching system is the system for adjusting the position of the irradiation part by using a radiotherapy plan image (DRR: Digital Reconstructed Radiograph) and an irradiation field verification image (LG: lineacgraphy) that is imaged prior to a treatment. This is characterized by including: an image obtaining means for obtaining the DRR, a shape data to create an irradiation field (FOV: Field Of View) and the LG; a pre-processing means for matching the sizes and positions between images of the obtained the DRR and the LG; an edge emphasizing means for emphasizing the edges of the images of the DRR and the LG; an FOV edge removing means for removing an FOV edge in the LG by using the obtained shape data; a binary means for converting the images of the DRR and LG into binary data; a thinning means for thinning the edges of the images of the DPR and LG that are converted into the binary data; a matching means for detecting the gaps of the DPR and LG; and a displaying means for displaying the matching result.
Japanese Laid-Open Patent Application JP-P 2007-267972A discloses an radiotherapy apparatus that can orient an irradiation axis of an X-ray, which is radiated from a therapeutic X-ray generating source, to a predetermined position always located at an irradiation target affected area, in order to irradiate the affected area with the X-ray of a moderate amount and attain a drop in the X-ray irradiation amount to the healthy tissue around the affected area. The radiotherapy apparatus includes: a gantry that can rotate around a first axis passing through an isocenter and can rotate even around a second axis crossing the first axis at the isocenter; an imaging apparatus arranged in the gantry; and a controller. The controller, from a plurality of positions of rotation angles that are defined as the angles around the first axis of the gantry, controls the imaging apparatus to take the images of a marker member, specifies the isocenter specification position based on each of the visual field positions of the images.
Japanese Laid-Open Patent Application JP-P 2006-21046A discloses an radiotherapy apparatus including: an O-shaped gantry; an irradiation head attached and movable to the O-shaped gantry and irradiating a irradiation field of a subject with therapeutic radiation; an X-ray source attached and movable to the O-shaped gantry and irradiating the irradiation field of the subject with diagnostic X-ray; a sensor array attached and movable to the O-shaped gantry and detecting transmitted X-ray which is the diagnostic X-ray transmitted through the subject and outputting as diagnostic image data. The sensor array and the X-ray source move in association with the movement of the irradiation head on the O-shaped gantry.
Japanese Laid-Open Patent Application JP-P 2004-97646A discloses an radiotherapy apparatus including: an irradiation head irradiating a irradiation field of a subject with therapeutic radiation; an X-ray source irradiating the irradiation field of the subject with diagnostic X-ray; a sensor array detecting transmitted X-ray which is the diagnostic X-ray transmitted through the subject and outputting as diagnostic image data. The sensor array moves in association with the movement of the irradiation head on the O-shaped gantry.